Collet chuck



T. B. HALL COLLET CHUCK March 5, 1946.

2 Sheets-Sheet 1 Filed July 15, 1943 iE-iiiiil INVENTOR. 7'5. HALLATTOEW March 5, 1946. HALL 2,396,006

COLLET CHUCK Filed July 15, 1943 2 Sheets-Sheet 2 IN V EN TOR.

TB. H444.

Patented Mar. 5, 1946 UNITED STATES PATENT OFFICE I coifjli 'fim TellerB. Hall, Angeles, Calif. Application July 13, 1943, Sdl'lll No. 494,4747 Claims. (Cl. 279-51) My' invention relates to a collet chuck and moreparticularly to that class known in the art as "nose-type" colletchucks.

One of the principal objects of my invention is to provide a colletchuck which is particularly simple and economical to manufacture, simpleto operate, and one which will not readily deteriorate or get out oforder.

An important object of this invention is to provide a chuck of thisclass whereby the material or stock to be held, or worked upon, may betightly gripped with a minimum of effort on the part of the operator,and in which such gripping effect is produced by a very slight,inclined, or tapered, wedge action, and which at thesame time servessubstantially to lock the material or 1 stock in the chuck without anyauxiliary means to lock the chuck in the clamping or runnin condition.

An object also of this invention is to provide simple lever means forshifting or operating the collet chuck whereby the material or stock maybe very tightly gri ped, and also easily and quickly released, with onlyslight effort on the part of the operator.

Another important object of this invention is to provide a novelcombination of inclined, wedge, 0r tapered surfaces for compounding theaction from the manually operated means to the material or stockgripping means, for tightly gripping such material or stock with aminimum of force by the manual operating means.

A further object of this invention is the provision of jaw grippingmeans which is diametrically contracted by .tapered or cone surfacesforced into engagement with each other by operating members, whichareforced radially inwardly, and which in turn force contraction of the jawmeans by other inclined surfaces. A further important object of thisinvention is to provide a collet chuck in which the collet or law meansmay be readily replaced by others of diflerent sizes, or in which slightvariation in the size of thematerial or stock to be held may be readilycompensated for by the addition or replacement of simple shim washers.

' Still another object of this invention is to provide simple means ofexpanding or opening the jaws of a Jaw means or the jaw portionsthereof.

A novel feature of this invention is the provision of simple means ofholding, separate jaws together as a unit.

A still further object of this invention is to provide simple means of010 11 8 the longitudinal 66 and.

so in one form mounted thereon, and showing by' slots, provided in thecollet. which form the separate jaw portions, thereby preventing foreignmaterial from entering the operating mechanism of the chuck;

An important object also of this invention is the provision of a noveladaptor whereby a device of this class may be accurately fitted to theFig. 1 is a fragmentary side elevation of the headstock of a latheshowing my collet chuck dotted lines various shifted positions ofcertain shiftable members thereof, and also showingfragmentarily thematerial or stock held thereby:

Fig. 2 is a longitudinal sectional view thereof,

25 in an open position, and showing by-dotted lines various partsshifted to their closed or stockholding positions, the view being takenthrough 2-2 of Fig. 4.

Fig. 3 is a similar fragmentary sectional view thereof, but showing bysolid lines the chuck in a. closed or stock-holding position, and by:iotted lines various parts open postions;

Fig. 3 is a fragmentary longitudinal section of a preferred form of theadaptor sleeve;

Fig. 4 is a fragmentary transverse view, partly in section, taken at 4-4of Fig. 2;

Fig. 5 is a fragmentary sectional view thereof taken through 55 of Fig.2;

Fig. 6 is a fragmentary longitudinal section. similar to that shown inFig. 3, but in an open position, of a slightly modified form ofconstruction;

Fig. 7 is a similar fragmentary longitudinal section thereof of anotherslightly modified form of construction, and showing primarily theadditionof a part to facilitate dismantling of the collet chuck shown inFigs. 2 and 3, for replacing the collet or associated parts;

Fig. 8 is another fragmentary longitudinal section view of still anothermodified form of construction, showing a means employed for holdingtogether separate laws of the Jaw means:

Fig. 9 is a fragmentary transverse section taken through 9-8 of P18. 8.

The drive spindle I, upon which my collet chuck is designed to bemounted, is shown here as the headstock spindle of a lathe, and is shownas mounted in the usual support. or housing 2 of the headstock of thelathe.

All of the collet chucks shown in the drawings, have a collet chuck bodyII which is hollow and is provided at one end with an internallythreaded portion I I which-is adapted to be carried by the threaded endof the lathe spindle I. As shown in the drawings, this threaded portionof the body is fitted to the threaded end of the spindle by means of anadaptor II, as will be hereinafter more speciflcallydescribed.

Within the body is mounted the jaw means which is operated or contractedby an operating sleeve I3, through the medium of operating members It.The sleeve It is slidably fitted around the body ll.

The jaw means, is shown in Figs. 2 and 3, as comprising a collet I!having at its outer end a plurality of diametrically contractable ,iawportions it", and having, at its inner end, a thin cylindrical portionit, which extends into a split cylindrical operating guide It. The lawportions are formed by splitting the outer end of the collet. Theoperating guide is provided intermediate'its ends with an annularchannel It for receiving the inner ends of the operating members H.These operating members are hardened pins which are arranged in a planeperpendicular to the axis of the collet chuck and radiate from its axis.The pins are forced inwardly by a slightly inclined or slightly taperedcone surface It at the outer end of the interior of the sleeve l3.

Experience has shown that the inclination of the operating surface maybe as low as 1 to obtain tight clamping action of the stock to be heldby the chuck, but in order to obtain eihcient clamping actioncommensurate with less shifting of a sleeve l3, this inclination maybeapproximately 3. As the sleeve I3 is shifted inwardly, the inclinedoperating surface l3 engages the outer ends of the operating members orpins l4, driving the same inwardly with great force. The inner ends ofthe plus I! are bevelled at H'- in such a manner that as'the pins aredriven inprovided with an inclined, tapered, or cone sur- 1 face II,which is adapted to be engaged by a conformingly inclined surface |5 atthe outer" sides of the law portions I5 of the collet. Thus, the jawportions or the collet are contracted diametrically as the collet isforced outwardly by the operating pins I I and the guide It. Experi-,ence has also shown that the inclination of the jaw portions and theouter end of the bore of the body ll may be as low as 8, but in order toobtain quickest results with the least shifting of the sleeve l3, theangle may be approximately 12.

The operating guide is constructed similarly to the collet, that is, itis split longitudinally at its outer end, as indicated by W in Figs. 2and 5, providing contractable portions it. As the operating pins llengage the bevelled ledges, they not only tend to force the guideoutwardly, but also aid in directly contracting the intermed ate portionof the guide, and therefore the intermediate portion of the collet.

Such combination of contracting forces upon the collet, namely, at theouter end and intermediate portion thereof, causes the jaws of thecollet to contract in a direction to assume positions parallel to theaxis of the collet, resulting in less mutilation of the stock or otherobject held by the collet and also causing tighter gripping of suchstock or other object.

The above construction gives a compounding wedge action between thesleeve l3 and the collet I! for not only tightly clamping or grippingthe stock, but for locking the same in the clamping position.

At the inner end of the cone shaped operating surface ll I have provideda clearance recess or channel it into which the outer ends of the pinsor operating members are adapted to be received so as to allow the innerends of the pins to be retracted into the. body in order to permit thewithdrawal of the collet l5 and guide The jaw portions I! of the colletmay be separated by rubber strips II, as shown best in Fig. 4.

Collets are usually made by providing longitudinal slots inwardly fromthe outer end of the collet, as indicated by It", and in the outer endsof these the rubber strips are located. Foreign particles, such aschips, find their way into the interior of the collet chuck through theslots, preventing proper functioning of the chuck and also damaging thesame. In order to minimize this result, the slotted contractible portionof the guide is tightly but slidably fitted around the slottedcylindrical portion of the collet backwardly from the jaw portions ofthe collet, with the slots of the guide staggered with respect to theslots of the collet. Thus the slots of the latter are closed backwardlyfrom the resilient spacer or rubber strip filled portions of the slotsopposite the jaw portions, and thereby preventing inward passage of suchforeign particles.

It is often desirable to use separate jaw mem-.

bers instead of a co11et,'as shown in Fig. 8 of the drawings. In suchinstances, segmental jaw members 2| are provided and circumferentiallyarranged within the body. These separate jaw members may be heldtogether by a continuous ring 22 located in a channel between the endsof the Jaw members. provided resilient strips i1 between the adjacentedges of the jaw members.

In Fig. 2 of the drawings, the head-stock spindle of the lathe is shownas threaded at one end I and is provided with a shoulder I at the innerend of the threaded portion. The adaptor sleeve l I, referred to above,is screwed over this threaded portion with its inner and against theshoulder l The threaded end ll of the body I i is screwed over anexternally threaded portion of the adaptor sleeve with the inner end llof the body engaging a shoulder ii at the inner end of the sleeve. Thethreads in the body are preferably smaller than those on the headstockspindle in order to provide a tighter fit of the sleeve in the chuck.

In order to facilitate the fitting of a chuck to the machine spindle ofthe purchaser or user of a new chuck, the adaptor sleeve I! may be soldin a rough condition shown ftagmentarily in Fig. 3'. The adaptor sleevemay be screwed on the spindle and machined in place to receive the newchuck. The rough adaptor sleeve has exterior threads I I" which iit theinterior threads In this instance, there is also assaooc 'at the innerend of the body. These threads form what may be termed a "sloppy" lit.The adaptor sleeve has portions l2 and I! at respectively the .inner andouter ends thereof which are intended to be machined or turned oil,while the adaptorisin place on the machine spindle, to form a tight orslip fit with corresponding portions. on the body ll.

In Fig. 1 of the drawings, thev headstock spindle support or housingI'supports a bracket SI, and the outer end of the bracket is providedwith ,a recess 3| which is positioned below andnear an annular channell3, at the inner end of the shifting sleeve IS. The sleeve i3 is shiftedby means of an operating lever 32 which has a loop portion 32 whichstraddles or fits around the sleeve l3. This loop portion carriespivoted shoes "which extend into the channel It". The lower end of thelever has a projection 32'' which extends into' the recess 3|. The outerside and lower end of the projection is curved, as indicated by'32. Thiscurvature permits the insertion of the projection into the recess 3 Ieven though the bracket is located close tothe sleeve l3. It alsoprovides the shortest possible lever betweenthe center of the shoes andthe fulcrum provided by the bracket 3!. Around the projection '32 isprovided a rubber washer 34 in order yieldably to space the lower end ofthe lever 32 above the bracket. The lower end of. the lever, immediatelyabove the projection 32 is substantially square,

' as indicated by 32, so as to raise, the lever slightly above its pivotbracket when the lever is shifted to either side of the verticalposition. Such con struction will permit the pivotal axis of theshoes tobe shifted in a substantially straight line along the axis of the chuckat all times. 1

In Fig. '7 of the drawings, I have provided a threaded collar in theouter end of the body ll, so as to permit ready removal of the collet'or jaw members from the chuck without the necessity of removing theother elements thereof.

In Fig. 6 of the drawings, I have shown a slightly modified form of mychuck in which the jaw members, designated 51, are provided with guidepins 52. at their outer and inner ends, and

gagedinthebodmprovidingbearingsurfaces.

for such pins securely to hold the pins for taking the backward reactionresultant from the forward force when applied to the shoulder I6 of theguide It for moving said collet forwardly with respect to the body.

The inner surface I! of the sleeve I3 is an annular inclined surface. Itis preferably in'the shape of a surface of revolution coaxial withrespect to the body II. also with respect to the spindle of the lathe.It is preferably such that a tracing thereof in a planethrough the axisof the sleeve is inclined with respect to said axis at an-angle slightlyless than the angle of friction for the inner surface of thesleeve' andthe outer end surfaces of the pins. Said tracing may depart from astraight line and can be somewhat curved; however, it is preferable thatthe inclination 6f the portion of the tracing at the point where thesleeve is brought into frictional engagea ment with the end of the pinis at the angle substantially hereinbefore mentioned, when the chuck isin stock gripping position.

It is to be understood that the use of mathematical specification of theshape of the inner operative surface l3 of the sleeve, where used in theclaims, is to be construed as meaning a surface substantially of thatshape and the type adapted for use in forcing and positioning the pinsinwardly sufficiently for opening and closingthe jaw means sufficientfor use in gripping and releasing stock having normal or reasonablevariation in stock sizes, and at the same time adapted to developsufficient friction to cause the chuck to stay locked while grippingstock.

ticular construction, combination, and arrangement' of parts andportions, and certain modificati ons thereof, I do not wish to belimited to the same, but desire to include in the scope of myinventionthe construction, combination, and arthe radially outer end' ofthe. guide pins shiftably rangement substantially as set forth in theappended claims.

I claim:

1. In a chuck, the combination with a support,

of a chuck mounted thereon, said chuck having a longitudinally slidablesleeve mounted therearound for operating the chuck, the sleeve having anannular channel, a sleeve shift lever straddling the sleeve and providedat its opposite sides with shoes adapted to ride in the channel. a pivotbracket mounted on the spindle support and procollet I1 and the sleevel6. This jaw means may 1 be, and is defined in the claims as, operatedby means of the pins M which radiate through the body. The pins orequivalent operating members for transmitting force from the operatingsurface l3 of the operating sleeve to the jaws may be considered asaportion of the jaw means.

Each of the species shown in the drawings and described in thespecification include a jaw means that embodies such an operatingmember. Each of these speciesincludes a hollow body I l, a sleeve is,and a jaw means of the type Just mentioned.

In the species describedwith reference toFigs. 2 and 3, the pins 14 andthe guide lB comprise means for transforming force, from an operatingsurface of the operating sleeve I 3 through the openings in the body I Iand against the'shoulder of the collet H, for moving the colletforwardly against the inclined surface II of the walls of the openingsin which the pins are slidably:en-

vided with a pivot recess, the lever having a pivot portion extendinginto said recess, the portion of the lever at the inner end of theprojection and adapted to rest with respect to the bracketbeingsubstantially flat and lying in a plane substantially perpendicular tothe longitudinal axis of the lever.

. 2. A colletchuck, comprising a hollow body,

- an operating guide mounted coaxially within the body, and slidablewith respect thereto, a collet. having a cylindrical shank mountedwithin the guide, the collet being split at the outer end; forming jawportions, the outer portions of the body and the collet havingconforming and interengaging inclined surfaces for contracting the jawportion when the guide is moved outwardly with the collet, and operatingpins radially arranged with respect to the body, and provided at theirinner ends with bevelled portions conforming with andengagingcorrespondingly inclined surface means of the guide, the latterinclined surface means being positioned inwardly from the inclinedsurface of 'the collet, the bevelled portions of the operating pins,when forced radially inwardly, being capable of forcing'the collet intoengagement with the inclined surface of the body.

3. A collet chuck, comprising a supporting body, a sleeve mounted overthe body and slidable longitudinally with respect thereto, an operatingmember radiating through the body, the interior of the sleeve havingoperating surface means inclined at an angle to its axis, said surfacemeans being adapted slidably to engage the outer portion of saidoperating memben'and jaw means circumferentially arranged within thebody and adapted to be operatively connected to the inner portion ofsaid operating member, and to be diametrically contracted when theoperating member is forced radially inwardly with the longitudinalmovement of the sleeve, the sleeve having an enlarged recess at theinner end of said surface means positioned most remote from said axis,said recess being capable of receivingthe outer end of the operatingmember when retracting the same within the body and outwardly withrespect to the axis, to facilitate the withdrawal of the jaw means fromthe body.

4. A collet chuck, comprising a hollow body, an operating guide mountedcoaxially within the body and slidable with respect thereto, a collethaving a cylindrical shank mounted within the guide, the collet beingslit at the outer end, forming jaw portions, the outer end of the guidebeing also slit, the slit portions of the guide being circumferentiallystaggered with respect to the slit portions of the collet, the outer endportion of the body having means for contracting the jaw portions whenthe guide is moved outwardly with the collet, and means for forcing theguide outwardly.

5. A collet chuck, comprising a hollow body, a cylindrical operatingguide mounted coaxially within the body and slidable with respectthereto, a cylindrical collet slidably mounted within the guide, theguide having an exterior annular channel with one end wall divergingoutwardly forming an inclined face, a plurality of pins radiatingoutwardly from the inclined ,face of the guide and provided at theirinner ends with inas'oaooc clined faces adapted to engage the inclinedface of the guide, and means at the outside of the body for forcing saidpins inwardly, the radially inner cylindrical wall of the channel of theguide being positioned radially inwardly from the inner ends of thepins, the outer end portions of the body and the collet havingconforming and interengaging inclined surfaces for contracting the Jawportions when the guide is moved longitudinally, with the collet by theinward shifting of the pins.

6. A collet chuck, comprising a hollow body, a

cylindrical operating guide mounted coaxially within the body andslidable with respect thereto, a cylindrical collet slidably mountedwithin the guide, the guide having an exterior annular channel with oneend wall diverging outwardly forming an inclined face, a plurality ofpins radiating outwardly from the inclined face of the guide andprovided at their "ends with inclined faces adapted to engage'theinclined face of the guide, a sleeve slidably mounted around the bodyand provided with an inner cone surface means adapted to engagecorrespondingly shaped outer ends of the pins, the inclination of thecone surface of said means. being such that the engagement thereof withthe outer ends of the pins causes sum'cient friction to lock the colletin contracted condition. a

'7. A collet chuck, comprising a supporting body, jaws arranged withinthe body for gripping stock to be machined, a plurality of pins radiallyarranged and slidably mounted in form-fitting holes in the body, asleeve slidably mounted around the body and provided with an inner conesurface means adapted to engage correspondingly shaped outer ends of thepins, the inner ends of the pins being operatively connected with .thejaw means in such a manner that shifting of the sleeve causes the pinsto be forced inwardly for closing the jaw means on the stock, theinclination of the cone surface of said means being such that theengagement thereof with the outer ends of the pins causes suflicientfriction to lock the jaw means in a closed position around the stock.

TELLER B. HALL.

